A key-defining characteristic of an MNO (which stands for “Mobile Network Operator”) is that an MNO must own or control access to a radio spectrum license obtained from a regulatory or government entity. A second key defining characteristic of an MNO is that an MNO must own or control the elements of the network infrastructure that are necessary to provide services to subscribers over the licensed spectrum. But, obtaining such licensed spectrum is a main issue for a company usually acting as a mobile network operator, which wants for example to offer new services and technologies (such as the 4G). Indeed, the process for obtaining such licensed spectrum is scarce and very expensive and extensive deployment of the new technology network also means large investment, and therefore need to consider the network sharing to overcome the this problem in order to reach adequate coverage at the initial launch of the new technologies.
In order to overcome this issue, under network sharing framework, several MNO may decide to share a licensed spectrum (such technique is called network sharing) and even some infrastructure elements including RBS (for “Radio Base Station”), RNC (for “Radio Network Controller”), BSC (for “Base Station Controller”), MSC (for “Mobile Switching Center”), SGSN (for “Serving GPRS Support Node”), and MME (for “Mobile Management Entity”) depending on the different network sharing scenarios. By implementing such a network sharing, the MNO may reduce their capital expenditure (CAPEX) by jointly using the infrastructure of the shared network, as well as cut operational expenditure (OPEX) by performing operations together.
Thus more and more MNO picture network sharing as a mechanism capable of ensuring future cost competitiveness and environment protection in the industry.
Hence, an MNO, owning a radio spectrum license may provide a dynamic spectrum access and management technique to the subscribers of an operator company under network sharing agreement (generally called secondary users compared to the primary users which are the subscribers of the MNO sharing its spectrum). Such dynamic spectrum access and management technique can be applied either in a context where there is only one MNO (which is called the intra-operator context), or either in the context where there are effectively at least two MNO which share a spectrum (which is called the inter-operator context or inter-operator network sharing agreement framework).
A first technique described in the document entitled “FlexibleandSpectrumAwareRadioAccessthroughMeasurementsandModellinginCognitiveR adioSystems” edited by J. Riihijärvi and R. Agustí in the context of the project FARAMIR (a European FP7 project) consists in establishing and using a Radio Environment Map (REM), which is a database, in order to speed up a spectrum sensing process within a dynamic spectrum access method. More precisely, such database comprises information on the radio environment of the shared network, including geographical features of the shared network, available services, spectrum policies of the MNO and regulations, location and activities of radio devices connected to the shared network, past experiences etc. Hence, such database enables to obtain a spectrum cartography of the shared network which combines measurements performed by different network entities (mobile terminals, base stations, access points) with geo-location information of theses network entities and runs simple and effective spatial interpolation techniques to achieve a map which indicates the level of interference experienced at each mesh over the area of interest.
Hence, a device of secondary user computes some parameters related to its emission power in order to prevent interference due to the attachment of the device of the secondary user to the network. Such task which can be quite time consuming is also a issue when several devices wants to access to the spectrum at the same time.
So far REM is intended to be used for intra-operator case, provides dynamic geo-located measurements on request, collected from every RAT domain that are stored and treated in the REM entity (encompassing REM management and storage modules). The post-treated REM data is then provided to the RRM (Radio Resource Management) entities for radio resources optimization purposes.
So the key contribution of REM is to improve the REM database by combining sensing and postpone processing. No clear procedures on how to access it by secondary users so far.
A second technique is described in the document U.S. 61/413,775 which discloses a wireless communication device of a secondary user, that transmits a geo-localization information to a database and requests information regarding primary users and available frequencies in the shared network. Such device comprises a geo-localization module 301, and such database can be stored either in an access point of the mobile operator network 1250, in the macro cell access point 1260, or in a femto node. It appears that such database provides to the wireless communication device the requested information. Therefore, the wireless communication device, after receiving such information, may adjust one or more parameters of the sensing module 305 of the wireless communication device. Then the processing module may determine the presence or absence of a device of a primary user based on the sensing.
However, the use of such technique, as the one related to the use of a REM, implies that a device of secondary user/device has to compute some parameters related to its emission power in order to prevent interference due to the attachment of a device of the secondary user to the shared network. Moreover, such technique doesn't work properly for dense access scenarios from secondary users due to apparent dynamic radio environment, dynamic traffic load, indoors and outdoors complex propagation model, and also variant radio performance of the devices of the primary users and of the devices of the secondary users. Another drawback of such technique, especially with the use of only a geo-localization information of the device of the secondary user, is that such geo-localization information may not be accurate (due to wrong position measurements). Therefore, the database could deliver to the device of the secondary user erroneous information about available frequencies or available communication channels.
Indeed, the technologies provided in priori arts mainly deals with database provisioning, no adequate architecture and mechanism to support the appropriate access from a new access points due to lacking of the knowledge in the said database on for example, operating profiles of the legacy nodes, radio profiles of different access nodes surround the new access points. Therefore the database have to leave large margin to protect the legacy users, and therefore when dense access points apply to access the spectrum in the same location, there is little opportunity to accommodate many access points with interference exempt principle.
Moreover, these techniques have other drawbacks. Indeed, it has been identified in doc S1-113150 during 3GPP TSG SA1_56#_San Francisco, November 2011, that within the inter-operator network sharing agreement framework, the resource allocated to each operator is in general pre-defined, within a cellular network, where both the cell referenced A and the target cell referenced Bare shared among three operators. For example:                Operator 1 owns 40% of the spectrum;        Operator 2 owns 40% of the spectrum;        Operator 3 owns 20% of the spectrum.        
If cell B is less loaded than cell A, and operator 1 has already used all its available share in cell B (i.e. 40%), operator 1 in cell A may not be able to offload any traffic in cell B if pre-defined resource allocation has been made, so that the users severed by operator 1 in cell B may suffer severe congestion even outage while some of the resources of operator 1 in cell A are idle. Thus the existing pre-defined static resource allocation scheme has some limitation on system performance and user experience.
In another example, a heterogeneous network with macro cells and HeNBs overlay, especially the HeNBs generally deployed in the residential area, it could be used depending on the life schedule of the people, that is, not permanently online, therefore in general may not need to be assigned with fixed frequency resources.
And in general, the resource management for HeNBs is separated from the resource management of the Macro layer based on the existing network architecture in 3GPP, in which the HeNB will be managed by H(e)MS, and configured by Configuration Management (CM), while NMS is taking the responsibility to manage the Macrolayer network elements. Thus even during the night, some spectrum on macrocell layer could be released when the base stations on macro cell layer enter into the energy saving mode, there is still constraints to all the unused spectrum and applied for HeNBs. Therefore there is need to set up a unified spectrum management entities.
Hence, there is a need to develop a technique, which facilitates the flexible spectrum access for both intra-operator scenario and inter-operator scenario within the licensed spectrum under network sharing context.